An individual homozygous dominant for the thumb shape mates with an individual homozygous recessive for thumb shape. What are the predicted genotypic and phenotypic ratios for the cross?

A punnet square can be described as a diagram which is made to check the outcomes of a cross.

To check the probability of the offsprings of a cross between homozygous dominant thumb shape parent with a homozygous recessive thumb shape parent, let's draw a punnet square:  

        t              t

T    Tt            Tt

T    Tt            Tt

The results of the punnet square depict that:

Genotype: All of the offsprings will be heterozygous for the thumb shape trait. Tt will be the genotype.

Phenotype: All of the offsprings will show the thumb shape like the thumb shape of the dominant parent.

"do a testcross with a homozygous recessive plant."

the "power" of a lens is its resolution power, or its ability to distinguish between to closely located points. with the low power lens, it is likely you will see the rough form of the hay and maybe some movement of dots around the hay. however, when observed with the high power lens, the detailed features of the hay become visible and the microbes being grown are more clearly visible.

i hope this you